Liquid analysis of mono-ethanolamine (MEA) solutions was performed by Fourier Transform Infrared (FTIR) spectroscopy by Attenuated Total Reflectance (ATR). Calibration spectra were obtained from a set of standard solutions of MEA. A calibration model for prediction of amine- and CO2 concentration in MEA solutions was obtained by PLS regression of the dataset. Online analysis of MEA solvent in a pilot plant was demonstrated by application of the developed model using a mobile setup for extractive sampling to an FTIR analyser. Our results show that liquid FTIR by ATR combined with multivariate methods such as PLS is well suited for analysis of amine solvents, both in the lab and for online process monitoring.